Multi-Touch Transparent Wireless Keyboard & Mouse
Transparent, wireless Multi-Touch Keyboard and Mouse designed by Jason Giddings are already commercially available. These devices are based on a touch screen technology known as Frustrated Total Internal Reflection (FTIR). There are infrared LEDs at the edge of the glass that diffuse the signal from the frustrated glass surface to the camera, which on its turn transfers the signal to the software that communicates with your computer. The mentioned software is open source so that it may be improved and optimized.
Via: Tuvie.com